1. Field of the Invention
The present invention relates to a styrenic resin composition, particularly to a styrenic resin composition which generate little unpleasant odor, which has good balance in physical properties thereof, which is adapted for various type of processing, and which is suitable for long-term operation.
2. Description of the Related Art
A styrenic resin composition is an impact resistant resin composition made by dispersing rubbery graft copolymer in a styrenic copolymer matrix. In practical application, styrenic resins can undergo several kinds of processing (for example, primary processing, such as injection molding and extrusion, and secondary processing, such as thermoforming and blow molding) to form a shaped commercial product. Under the current trends of environmental protection and of making the work place more pleasant for the workers, more attention is being paid to the smell of the work place. It is well known that workers are exposed to the unpleasant smell when the styrenic resins undergo various kinds of processing. It is therefore an important subject in the art to develop a styrenic resin composition which generates little unpleasant odor during its processing and which enables an operator to bear long-term exposure to the same.
In order to eliminate the unpleasant odor generated during the processing of the styrenic resin, the addition of antioxidants and enhanced devolatilization have been suggested so as to reduce the content of the residual monomer, thereby reducing the unpleasant odor. However, the improvement achieved thereby is not significant since only one of the many sources of the unpleasant odor is reduced and thus, the improvement in reducing the unpleasant odor is limited. The above suggested method is still not suitable for long-term exposure of an operator, who is carrying out operations such as injection and extrusion of the styrenic resin. This is because the aforementioned method only delays the operator's sensing of the unpleasant odor.
Accordingly, a styrenic resin composition which generates little unpleasant odor, which is adapted to various kinds of processing, and which is suitable for long term operations is proposed to overcome the aforementioned drawbacks, without adversely affecting the balance in physical properties of the resin composition.